Step-by-step explanation:
The process of DNA replication, in which a new strand of DNA is synthesized using an existing strand as a template, is mediated by enzymes called DNA polymerases. During DNA replication, DNA polymerase moves along the template strand and adds nucleotides to the growing complementary strand according to base-pairing rules: adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G).
The selection of the correct nucleotide to add to the growing strand is based on the base-pairing rules, which are determined by the specific hydrogen-bonding interactions between the nucleotides. A nucleotide with adenine (A) will only bond to a nucleotide with thymine (T), and a nucleotide with cytosine (C) will only bond to a nucleotide with guanine (G).
The DNA polymerase enzyme has a binding pocket that is complementary in shape to the nucleotide that it is adding, allowing for only the correct nucleotide to be brought and bonded to the growing strand. In addition, DNA polymerase has a proofreading mechanism that allows it to detect and correct errors in nucleotide incorporation.
Overall, the specificity and accuracy of DNA replication is determined by the base-pairing rules, the shape complementarity between the nucleotides and the DNA polymerase enzyme, and the proofreading mechanisms that ensure fidelity in the copying process.